The present invention relates to granular laundry detergent compositions which provide enhanced hydrophilic soil, inter alia, clay, removal benefits. The laundry detergent compositions of the present invention combine a zwitterionic hexamethylene diamine with a surfactant system to produce either a granular free flowing or tablet composition. The present invention further relates to methods for cleaning fabric having heavy clay soil deposits.
Fabric, especially clothing, can become soiled with a variety of foreign substances ranging from hydrophobic stains (grease, oil) to hydrophilic stains (clay). The level of cleaning which is necessary to remove said foreign substances depends to a large degree upon the amount of stain present and the degree to which the foreign substance has contacted the fabric fibers. Grass stains usually involve direct abrasive contact with vegetative matter thereby producing highly penetrating stains. Clay soil stains, although in some instances contacting the fabric fibers with less force, nevertheless provide a different type of soil removal problem du to the high degree of charge associated with the clay itself. This high surface charge density may act to repel some laundry adjunct ingredients, inter alia, clay dispersants, thereby resisting any appreciable solublizing of the clay into the laundry liquor.
A surfactant per se is not all that is necessary to remove unwanted clay soils and stains. In fact, not all surfactants work equally well on all types of stains. In addition to surfactants, polyamine hydrophilic soil dispersants are added to laundry detergent compositions to xe2x80x9ccarry awayxe2x80x9d clay soils from the fabric surface and to remove the possibility that the clay soil will be re-deposited upon the fabric. However, unless the clay can be initially dispersed away from the fabric fiber, especially in the case of hydrophilic fibers, inter alia, cotton, the soils can not be effectively removed from the fabric.
There is a long felt need in the art for granular laundry detergent compositions which can effectively solublize embedded clay and other hydrophilic soils from fabric. There has further been a long felt need for a method for cleaning hydrophilic soils from fabric wherein the hydrophilic soils are effectively solublized into the laundry liquor.
The present invention meets the aforementioned needs in that it has been surprisingly discovered that certain zwitterionic hexamethylene diamines in combination with a surfactant system comprising provides enhanced removal of clay and other hydrophilic soils from fabric.
The first aspect of the present invention relates to a laundry detergent composition comprising:
a) from about 0.01%, preferably from about 0.1%, more preferably from about 1%, most preferably from about 3% to about 20%, preferably to about 10%, more preferably to about 5% by weight, of a zwitterionic hexamethylene diamine having the formula: 
wherein R is an alkyleneoxy unit having the formula:
xe2x80x94(R1O)xR2 
wherein R1 is C2-C4 linear alkylene, C3-C4 branched alkylene, and mixtures thereof; R2 is hydrogen, an anionic unit, and mixtures thereof; the index x has the value of from about 15 to about 35; Q is a quaternizing unit independently selected from the group consisting of C1-C8 linear alkyl, C3-C8 branched alkyl, benzyl, and mixtures thereof; X is a water soluble anion in sufficient amount to provide electronic neutrality;
b) from about 0.01%, preferably from about 0.1% more preferably from about 1%, most preferably from about 10% to about 80% by weight, preferably to about 60%, most preferably to about 30% by weight, of a surfactant system comprising one or more surfactants selected from the group consisting of nonionic, anionic, cationic, zwitterionic, ampholytic surfactants, and mixtures thereof; and
c) the balance carriers and adjunct ingredients.
The present invention further relates to laundry detergent compositions in the form of a solid tablet or pill wherein the zwitterionic hexamethylene diamine has surprisingly been discovered to serve as a process aid or tablet binder in addition to providing superior cleaning properties.
The present invention also relates to a method for removing hydrophilic stains from fabric by contacting fabric in need of cleaning with an aqueous solution comprising at least 1 ppm (0.0001%), preferably at least 5 ppm (0.0005%), more preferably at least 10 ppm (0.001%) of one or more zwitterionic hexamethylene diamines.
These and other objects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
The present invention relates to the surprising discovery that the combination of a zwitterionic diamine having a hexamethylene backbone and a surfactant system provides enhanced benefits for removal of clay soil from fabric especially clothing. It has also been surprisingly discovered that the presence of one or more quarternized hexamethylene diamines having at least one anionic unit capped alkyleneoxy backbone substitution provides a formulation aid when processing granular, especially tablet, laundry detergent compositions. As described herein below, the quaternary ammonium hexamethylene diamine and surfactant system can be combined with a wide variety of adjunct ingredients to provide granular laundry detergent compositions having increased clay removal properties.
The laundry detergent compositions of the present invention may take any form, for example, granular, powder, or tablet; a preferred form, further described herein below, is tablet form.
The following is a detailed description of the require elements of the present invention.
Zwitterionic Hexamethylene Diamines
The granular laundry detergent compositions of the present invention comprise from about 0.01%, preferably from about 0.1%, more preferably from about 1%, most preferably from about 3% to about 20%, preferably to about 10%, more preferably to about 5% by weight, of a zwitterionic hexamethylene diamine having the formula: 
wherein R is an alkyleneoxy unit having the formula:
xe2x80x94(R1O)xR2 
wherein R1 is C2-C4 linear alkylene, C3-C4 branched alkylene, and mixtures thereof; preferably ethylene.
R2 is hydrogen, an anionic unit, and mixtures thereof. Non-limiting examples of anionic units include xe2x80x94(CH2)pCO2M; xe2x80x94(CH2)qSO3M; xe2x80x94(CH2)qOSO3M; xe2x80x94(CH2)qCH(SO2M)xe2x80x94CH2SO3M; xe2x80x94(CH2)qCH(OSO2M)CH2OSO3M xe2x80x94(CH2)qCH(SO3M)CH2SO3M; xe2x80x94(CH2)pPO3M; xe2x80x94PO3M; and mixtures thereof; wherein M is hydrogen or a water soluble cation in sufficient amount to satisfy charge balance. Preferred anionic units are xe2x80x94(CH2)pCO2M; xe2x80x94SO3M, more preferably xe2x80x94SO3M. The indices p and q are integers from 0 to 6. Preferably from about 85%, more preferably from about 90%, most preferably from about 95% of all R2 units which comprise an aggregate sample of the zwitterionic polyamine have R2 units which are anionic units. It will be understood by the formulator that some molecules will be fully capped with anionic units, while some molecules may have two R2 units which are hydrogen. However, most preferably from about 95% of all R units present will be capped with one or more anionic units described herein.
The index x has the value of from about 15 to about 35 and represents the average number of alkyleneoxy units which are present. Depending upon the method by which the formulator chooses to form the alkyleneoxy units, the wider or narrower the range of alkyleneoxy units present. Preferably the range of alkyleneoxy units in plus or minus two units, more preferably plus or minus one unit. Most preferably each R group comprises the same number of alkyleneoxy units. The index x is preferably from 20 to 30. A preferred value for x is 24, especially when R1 comprises entirely ethyleneoxy units.
Q is a quaternizing unit independently selected from the group consisting of C1-C8 linear alkyl, C3-C8 branched alkyl, benzyl, and mixtures thereof; preferably methyl or benzyl, most preferably methyl.
X is a water soluble anion in sufficient amount to provide electronic neutrality. To a great degree, the counter ion X will be derived from the unit which is used to perform the quarternization. For example, if methyl chloride is used as the quaternizing agent, chlorine (chloride ion) will be the counter ion X. Bromine (bromide ion) will be the dominant counter ion in the case where benzyl bromide is the quaternizing reagent.
A preferred zwitterionic hexamethylene diamine according to the present invention has the formula: 
wherein X can comprise any suitable counterion.